Other events

Professor Pete Langdon (Department of Geography and Environment, University of Southampton)

Tipping points in lake ecosystems: how well can we predict them?

Lake ecosystems are changing rapidly under growing anthropogenic pressure, with many moving from one functioning state to another across poorly understood thresholds. These changes can be termed regime shifts, which we define as any substantial reorganization of a complex system with prolonged consequences. The cusp between states is a tipping point, where a small perturbation may suffice for the system to move from one state to another. Moving the system back to the previous state may require much larger perturbations, or even be effectively impossible where internal processes and feedback loops reinforce the new state, as in a fold bifurcation. Consequently, being able to warn of an approaching tipping point before it is reached may allow time for policies to be put in place that would avoid it. Hence, by understanding the mechanisms preceding a tipping point through dynamical systems theory we can attempt to predict such a change through leading indicators, or early warning signals (EWS). This seminar will explain the issues underlying the detection of tipping points, and whether we can predict them in lake ecosystems, through EWS and/or changes in ecosystem architecture. The latter part will attempt to show how an understanding of the system state behaviour as ecological boundaries are reached can help to define regional safe operating spaces.